Spiced Indian Yogurt (Chaas) Recipe

[Photograph: Prasanna Sankhe] 3 tablespoons plain yogurt 4 cups water 1/4 teaspoon black salt (see note) Kosher salt 2 teaspoons toasted and ground cumin seeds (divided) 1 serrano chile lightly bruised (optional) 2 teaspoons finely chopped cilantro leaves, plus whole leaves for garnish In a large bowl, …